1. Field of the Invention
This invention, in general, relates to the field of optical image transfer. In particular, this invention relates to a wide angle image transfer system capable of transforming images up to 360.degree. in conjunction with the taking and projection of pictures.
2. Description of the Prior Art
In many training situations the presentation of an external environment is a necessity in order for the trainee to perceive visual cues, and thereby learn to take actions or manipulate training equipment to maximum advantage for a given training situation. A particularly useful approach to reality in display is to generate a 360.degree. wide-angle presentation to produce the effect of the observer being in the center of scene activity.
One such device of the prior art which may be utilized to generate a 360.degree. wide-angle presentation is the Optical System for 360.degree. Image Transfer, of U.S. Pat. No. 4,012,126 by Gottfried R. Rosendahl and Wiley V. Dykes. Disclosed therein is an optical transfer system for 360.degree. image transfer in which spaced primary and secondary hyperbolically surfaced mirrors are combined with a refractive lens system and are held in spaced relationship by a transparent envelope having inner and outer surfaces generated from the near focal point of the primary mirror. The primary mirror coincides with the entrance pupil of the system in order to avoid aberrations by the envelope within a pencil of rays originating from an object or image point and particularly between pencils originating at different object or image points. The aforementioned primary and secondary mirrors are, in turn, spaced and confocally arranged. The near focal point of the secondary mirror approximates the apex of the primary mirror, and the far focal points of the primary and secondary mirrors coincide to form a confocal set of mirrors.
With regard to the aforementioned Optical System for 360.degree. Image Transfer disclosed in U.S. Pat. No. 4,012,126, the lens system included therein is susceptible to damage because of thermal shock, particularly the lens elements of the system fabricated from calcium fluoride. In addition, the lens system does not adequately correct for primary and secondary color which, in turn, will result in a lack of sharpness in a produced image because of chromatic aberrations. Further, the lens system of the above mentioned Optical System for 360.degree. Image Transfer does not operate in exactly the same manner as the subject invention and contains a combination of elements that is somewhat different from that of the present invention.